Monday, February 1, 2010

Welcome to our third Get Growing entry. This series will span 12 months, and is designed to help aspiring vegetable gardeners get out of the kitchen and into the garden. On the first of each month, we will discuss one garden project for the novice vegetable gardener. Because we are located in Houston, Texas, our growing conditions differ from many parts of the English-speaking world. To help guide gardeners in cooler climates, our Get Growing partner is Daphne of Daphne's Dandelions. Daphne gardens in Boston, and she will be providing monthly advice for Northern gardeners (although her excellent site is a wonderful resource for gardeners everywhere). For Get Growing in February, Daphne discusses compost: what it is, how to make it, and how to use it Regardless of where you live, her advice is invaluable.

Starting Tomatoes in February

February 15th is the average last frost date for Houston. This means that there are many summer vegetable seeds we can start in February, but please first read our words of caution about "average" last frost dates. You will need to be prepared to protect your seedlings from an unseasonable frost which means using insulators or covers, or keeping your seedlings in pots so they can be brought inside if necessary.

Tomatoes are one of those vegetables that everyone stresses about growing. There are diseases and insects to worry about, birds will attach your fruit just before it's ready to pick, intense rains may cause blossom-end rot, and our hot weather will stop fruit production early in the summer. With all these issues, we debated about presenting tomatoes as this month's gardening project. But home-grown tomatoes are so far superior to what is available for purchase, we think it's worth the challenge. And, we're going to try to keep it very simple for the novice gardener so that you're guaranteed to succeed.

Why start tomato seeds now when there's still a risk of a late frost?

Tomato fruit tends to set in a fairly narrow temperature window, and once it gets too hot (night time temperatures over 75° or day time temperatures over 92°), your plants may not produce fruit. In Houston, that can happen as early as June, so the idea of tomatoes as a "summer" vegetable doesn't work in Zone 9. Higher temperatures also make tomato plants more susceptible to disease and insects. If you wait until tomato transplants start showing up at the garden center in April or May, your plants don't have much chance of success. Starting your seeds now is a bit of a gamble, but if you start them in pots (which we recommend), you can bring them indoors if we get a late frost. And, starting with seeds instead of plants has a few benefits:

you can select from thousands of varieties

buying seeds is much cheaper than purchasing plants

you can start your plants much earlier

you will know your plants are healthy, organic and disease-free

you will know what you're growing (we have purchase mis-labeled plants more than once, ending up with a huge red tomato that was supposed to be a yellow cherry tomato, for example)

Preparing the garden

First, select a spot that gets full sun. We grow our tomatoes along our driveway in a section of the garden that faces south and gets sun from morning until late in the day.

Tomato plants need fertile soil, and the easiest way to provide this is to prepare your soil ahead of time. We have been saving bags of leaves, pine needles and grass clippings all winter, and we simply add these to the soil ahead of time. If you have a compost pile, amend generously now. If you start with fertile soil, your plants should thrive without much intervention later in the season.

If you experience heavy rains like we do in Houston, a raised bed is not a bad idea.

Because tomatoes can be susceptible to soil-bourne diseases, try to select a spot where you have not recently grown tomatoes. Some suggest selecting a spot where no solonocae (eggplants, peppers, etc) have recently grown.

Plan to mulch heavily around your tomato plants.

Choosing your tomato varieties

If you are a novice tomato grower, focus on cherry tomatoes. These tomatoes are much easier to grow in in Zone 9, and you will be rewarded with heavy production for a long period, even in the hottest months, if you grow these small tomatoes. Two of our favorite varieties are Yellow Pear (above) and Matt's Wild Cherry (below). Standard tomatoes are much fussier and challenging, but the pay-off is amazing. If you want to also grow a full-size tomato, select one that suits your preferences for flavor, size and color. Our instructions below work for cherry or standard tomatoes.

Starting your seeds and Transplanting

We recommend that you start your seeds in grower pots. If you start with good seeds (see our sidebar for some of our favorite seed suppliers), tomatoes have an excellent germination rate, so you don't need to start thousands of seeds. Keep the seedlings watered and make sure they get lots of light so they don't become too leggy. Once they have developed three or four sets of leaves, pinch off the bottom leaves and transplant into the garden. Plant so that the spot where you pinched the leaves is BELOW the soil level. Roots will develop here, producing a plant with extensive, deep roots that will help protect the plant from our summer heat.

Drive a stake into the ground when you transplant the seedling, and gently secure the seedling to the stake. We use bamboo from our garden and recycled twist ties for this.

If you plan to use cages, select a sturdy one, and place it in the ground when you transplant the seedlings. If you wait until the seedling grows into a large plant first, you risk seriously damaging the plant when you try to squeeze it into the cage.

Seedling care

Tomatoes like consistent water, although not too much. Here in Houston we have sudden, intense rain storms which make that difficult. Our advise is to not stress about what you can't control, and just water your seedlings at regular intervals if there is no rain. Mulch will help keep the soil evenly moist. If you started with fertile soil, you should not need to amend during the growing season.

As the seedlings develop, they will form suckers. You can read our post on suckers and their removal, and how to convert suckers into new seedlings to share with friends and family.

Fruit Production

Tomatoes have "perfect" flowers which means there are no male and female flowers. This generally means easier fruit production, but if you don't want to take any chances, you can always hand-pollinate your plants. This is extremely easy, and one of the few gardening projects that produces results in just a few days. If you have the time, we highly recommend hand-pollination.

Fruit Harvest

Cherry tomatoes do not tend to have significant pest problems, so we leave them to fully ripen on the plant. They taste amazing this way. They grow in clusters, so you should be able to harvest several at one time. With full-size tomatoes, we have often waited one day too long only to find a big chunk taken our of our tomatoes by a bird, or to see cracks forming in the tomato skin. We suggest harvesting your full-size tomatoes when they are close to mature, then letting them fully ripen in the safety of your kitchen.

Seed Collection

If you are growing an heirloom tomato variety (as opposed to a hybrid variety), you should collect seeds from your biggest and most beautiful fruit. Since tomatoes have "perfect" flowers, there's little risk of cross-pollination even if you are growing more than one tomato variety. This means your seeds will produce seedlings true to their variety as opposed to a combination of yellow pear and wild cherry.

Simply squeeze the seeds into a thin-meshed sieve, then rinse well with clean water. Spread the seeds out on paper towels to dry, then store in an envelope or plastic bag for next year. Be sure to label your seeds with the collection date and variety name. In Zone 9, we start a second crop of tomatoes in the fall, so you may end up using these collected seeds later this year.

Organic Gardening

We don't use chemicals or pesticides in our garden. We don't want to expose ourselves, our kids, and our neighbors to those chemicals. Our garden has been organic since we purchased our house 14 years ago, and we have never had a pest problem with one exception, the squash vine borer, which wiped out our zucchini and squash plants last year. The squash vine borer is the caterpillar of a moth which lays it's eggs on squash plants.

Similarly, tomatoes attract a moth which lays eggs that hatch into the tomato hornworm, a surprisingly beautiful caterpillar despite it's nasty ways. We had a few hornworms last year, easy to spot when you notice plant stems that are missing all their leaves, but most were eliminated early on by garden predators. We just picked off the few we discovered (and sent them to an early death). They did not seriously interfere with our tomato fruit production, and are certainly not worth straying from your commitment to organic gardening.

Our natural predators include dragonflies and lady bugs (above) as well as birds, frogs, wasps, and assassin bugs. Above is a wasp nest (made out of mud) with two pupa inside. Unfortunately, this nest was built right above our kitchen door and the wasps got a little too aggressive every time we entered or left the house, so we knocked down the nest. The wasps returned to the spot of the nest for several days before building a new one under our roof overhang.

Reading about Tomatoes

If we have sparked an urge to read and learn more about tomatoes, there are several excellent books that we recommend. Smith and Hawken has published a nice guide to heirloom tomato varieties, and Amy Goldman's book on heirloom tomatoes is full of gorgeous pictures that will make it almost impossible for you to choose only one variety. We also recommend Elioit Coleman and Edward Smith for good, basic tomato growing advice. Online, Urban Harvest has several excellent articles and lots of useful advice for growing tomatoes and other vegetables in Houston (or similar climates).

5 comments:

if you are looking for more information on USDA plant hardiness zones, there is a detailed and interactive USDA plant hardiness zone map at http://www.plantmaps.com/usda_hardiness_zone_map.php which allow you to locate your USDA zone based on zipcode or city.

Apparently wasps are very territorial so once they see a nest in one place they won't try to build their own there. Based on this idea I've seen fake wasp nests for sale at nurseries or gardening centers.